GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 22 Jan 2019, 06:56

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
  • The winners of the GMAT game show

     January 22, 2019

     January 22, 2019

     10:00 PM PST

     11:00 PM PST

    In case you didn’t notice, we recently held the 1st ever GMAT game show and it was awesome! See who won a full GMAT course, and register to the next one.
  • Key Strategies to Master GMAT SC

     January 26, 2019

     January 26, 2019

     07:00 AM PST

     09:00 AM PST

    Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.

Is y < 0 (1) x + y = 1 (2) x^2 < y^2

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52385
Is y < 0 (1) x + y = 1 (2) x^2 < y^2  [#permalink]

Show Tags

New post 10 Jun 2018, 03:42
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

50% (02:13) correct 50% (01:40) wrong based on 36 sessions

HideShow timer Statistics

Manager
Manager
avatar
B
Joined: 10 Jun 2018
Posts: 55
Location: Australia
Concentration: Technology, General Management
GPA: 2.88
WE: Science (Pharmaceuticals and Biotech)
Re: Is y < 0 (1) x + y = 1 (2) x^2 < y^2  [#permalink]

Show Tags

New post 10 Jun 2018, 05:53
1
Well, firstly neither statement is sufficient. Testing numbers is enough to figure this out.

(1) Let y = -1 (so y < 0), x = 2. Let y = 2 (so y > 0), x = -1. Since with (1) y can be less than 0 or not, it is not sufficient.

(2) Let y = -3 (so y < 0), then y^2 = 9. So long as x^2 can be <9 then y = -3 is valid. We can have x be 1 or 2 or whatever and it'd be valid. Now, let y = 3 (so y > 0), then y^2 = 9. Same case as above. Since y can be less than 0 or not, (2) is also not sufficient.

Together? Well let's re-write the equation in statement (1): x + y = 1 <=> x = 1 - y.

Thus with statement (2), we have (1-y)^2 < y^2. I can't solve this normally as I haven't practiced inequalities in a long time, so let's plug in numbers XD. Let's try y = 0. In this case, we have 1 < 0, which is impossible. Let's try y = 1, in which case we have 0 < 1. Let's try a number larger than 1. Say 2. We then have 1 < 4, which is fine. In fact, any positive number >= 1 will have the effect, because then the absolute value of 1-y will always be 1 less than y, and thus (1-y)^2 will always be < y^2. Now, what about y < 0? Say -1? We then have 4 < 1, which is impossible. We can try a much larger negative number, like -100. We'd have 101^2 < 100^2, again is not possible. We have something similar to the previous case, except that the absolute value of 1-y will always be 1 higher than y, which is impossible due to the inequality. If we tested fractions too, we'd figure out that some of the fractions are not possible, but it is unnecessary to test them as we only care if y is < 0 or not. y may also not be < than 1/2 for example, but that still fits if we determine that y must be > 0, which in this case we do.

Thus, answer is C.
_________________

Not a professional entity or a quant/verbal expert or anything. So take my answers with a grain of salt.

Intern
Intern
User avatar
B
Joined: 11 Sep 2017
Posts: 46
GMAT 1: 600 Q42 V31
Reviews Badge
Re: Is y < 0 (1) x + y = 1 (2) x^2 < y^2  [#permalink]

Show Tags

New post 23 Jul 2018, 00:32
1
Bunuel wrote:
Is y < 0

(1) x + y = 1
(2) x^2 < y^2


Clearly 1 and 2 both are individually insufficient

lets try for option C
rearranging as we know that square terms are positive
we get,
X^2 - Y^2 < 0
(X+Y)(X-Y) < 0
But X + Y = 1 (From statement 1)
So X-Y < 0
X < Y
So for X < Y statement 1 will never be true if Y<0
Hence sufficient, Y is not < 0

ANSWER : C
GMAT Club Bot
Re: Is y < 0 (1) x + y = 1 (2) x^2 < y^2 &nbs [#permalink] 23 Jul 2018, 00:32
Display posts from previous: Sort by

Is y < 0 (1) x + y = 1 (2) x^2 < y^2

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.